Si-C bond strength in cage-like methylsilsesquioxanes and methyl-bearing metalosilsesquioxanes estimated from DFT calculations

Abstract

The strength of the Si-C bond in cage-like methylsilsesquioxanes and methyl-bearing coppersilsesquioxanes was estimated from the Mulliken bond populations calculated using the B3LYP density functional method. The estimation was performed using a linear relation between Mulliken bond populations and the calculated Si-C bond strengths in a series of silanes, which is in good agreement with the published data. The introduction of Cu atoms into the silsesquioxane cage leads to a decrease in the Si-C bond strength, which can be a reason for a considerable decrease in the thermal stability of metalorganosilsesquioxanes compared to their siloxane analogs.